Implantable medical devices, such as cardiac pacemakers or defibrillators, typically include a metal housing having a feedthrough device (often referred to simply as a feedthrough) which establishes electrical connections between a hermetically sealed interior of the metal housing and an exterior of the medical device. Feedthroughs typically include an insulator and a frame-like metal ferrule disposed about a perimeter edge of the insulator. The ferrule is configured to fit into a corresponding opening in the metal housing, with the ferrule typically being welded to the housing to ensure a hermetic seal with respect to the interior of the housing. Electrical conductors or “feedthrough pins” extend through the insulator to provide electrical pathways between the hermetically sealed interior of the housing and an exterior of the medical device. The insulator electrically isolates the feedthrough pins from one another and from the metal ferrule and housing.
The ferrule and insulator are typically joined to one another via a brazing or soldering process. Forming the metal ferrule (typically via a machining process) to meet the tight tolerances required to maintain a desired gap (about 10-50 μm) between the ferrule and insulator that is necessary to achieve a quality braze joint is difficult. Additionally, if the gap is not maintained during the brazing process or if the brazing itself is not properly performed, a weak joint may be formed between the ferrule and the insulator that may lead to premature failure of the implantable device.
For these and other reasons there is a need for the embodiments of the present disclosure.